+PH/13 Domain literals for IPv6 were not recognized unless IPv6 support was
+ compiled. In many other places in Exim, IPv6 addresses are always
+ recognized, so I have changed this. It also means that IPv4 domain
+ literals of the form [IPV4:n.n.n.n] are now always recognized.
+
+PH/14 When a uid/gid is specified for the queryprogram router, it cannot be
+ used if the router is not running as root, for example, when verifying at
+ ACL time, or when using -bh. The debugging output from this situation was
+ non-existent - all you got was a failure to exec. I have made two
+ changes:
+
+ (a) Failures to set uid/gid, the current directory, or a process leader
+ in a subprocess such as that created by queryprogram now generate
+ suitable debugging ouput when -d is set.
+
+ (b) The queryprogram router detects when it is not running as root,
+ outputs suitable debugging information if -d is set, and then runs
+ the subprocess without attempting to change uid/gid.
+
+PH/15 Minor change to Makefile for building test_host (undocumented testing
+ feature).
+
+PH/16 As discussed on the list in Nov/Dec: Exim no longer looks at the
+ additional section of a DNS packet that returns MX or SRV records.
+ Instead, it always explicitly searches for A/AAAA records. This avoids
+ major problems that occur when a DNS server includes only records of one
+ type (A or AAAA) in an MX/SRV packet. A byproduct of this change has
+ fixed another bug: if SRV records were looked up and the corresponding
+ address records were *not* found in the additional section, the port
+ values from the SRV records were lost.
+
+PH/17 If a delivery to a pipe, file, or autoreply was deferred, Exim was not
+ using the correct key (the original address) when searching the retry
+ rules in order to find which one to use for generating the retry hint.
+
+PH/18 If quota_warn_message contains a From: header, Exim now refrains from
+ adding the default one. Similarly, if it contains a Reply-To: header, the
+ errors_reply_to option, if set, is not used.
+
+PH/19 When calculating a retry time, Exim used to measure the "time since
+ failure" by looking at the "first failed" field in the retry record. Now
+ it does not use this if it is later than than the arrival time of the
+ message. Instead it uses the arrival time. This makes for better
+ behaviour in cases where some deliveries succeed, thus re-setting the
+ "first failed" field. An example is a quota failure for a huge message
+ when small messages continue to be delivered. Without this change, the
+ "time since failure" will always be short, possible causing more frequent
+ delivery attempts for the huge message than are intended.
+
+PH/20 Added $auth1, $auth2, $auth3 to contain authentication data (as well as
+ $1, $2, $3) because the numerical variables can be reset during some
+ expansion items (e.g. "match"), thereby losing the authentication data.
+
+